Motor-controller.



N. L. MORTENSEN.

MOTOR CONTROLLERQ APPLICATION FILED ROY/.15. 1911.

1,227,177. P51611161 May 22, 1917.

Amy-9' -za;m?

f 1 I z a Egg 7 14 j 1 :1 1 i I 4 11 Z4 I W l I L dag? UNITED STATES PATENT OFFICE. I

NIEIIS L. MORTENSEN, OI MILWAUKEE, WISCONSIN, ASSIGNOB TO THE CUTLER- HAMMEB MFG. CO., 01 MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

uoron-conrronnnn.

Specification of Letters Patent.

Application filed November 15, 1911. Serial No. 660,387.

. electric motors.

My invention is particularly applicable to the control of electric motors used for hosting and lowering where dynamlc braking and power reversal or kick-off are desired for lowering. My invention however, is

diagrammatically illustrated in the accompanying drawing. It should be understood however, that my invention is not -l1m1ted to the specific embodiment thereof selected for the purpose of illustration;

In the accompanying drawing,

Figure 1 is a diagrammatic view of the controller and circuit connections therefor and, Figs. 2, 3 and 4 are diagrammatic views showing in simplified form certain of the connections established by the controller of Fig. 1.

Referring to Fig. 1 of the drawlng I have diagrammatically illustrated a motor 1 of the series type, having an armature A and a series field winding F. It should be understood however, that the motor 1 might be of other types if preferred. It may be assumed that this motor is employed for hoisting and lowering purposes and that a mechanical brake is used in conjunction therewith in the usual manner. have accordingly diagrammatically illustrated a brake 'coil B for electrically controlling the mechanical brake in the usual manner.

A controller C of the drum type is shown foraccomplishing the desired control of the motor which is supplied with current from lines L to L. The controller C may in practice be of any preferred type. As diagrammatically illustrated it is provided with a series of stationary contact fingers disposed between sets of contact segments which it ma be assumed are mounted upon amovable rum, said drum being movable in opposite directions from a central position to bring the desired sets of segments into engagement with their respective contact fingers. In practice I prefer to divide the drum into insulated sections as indicated by the heavy black line XY, as this per-' Patented May 22, 1917.

mits of the mounting of the segments of the different sections directly upon a common conducting member, thus eliminating the necessity of specially connecting the segments as illustrated. The central stationary contact fingers I have designated as 2- to' 15 inclusive. The left hand segments I have designated with the same numerals as the contacts with which they engage but with the exponent a. I have also designated the right hand segments by the same numerals as the contact fingers with which they engage but with the exponent b. It may be assumed that the drum is moved to bring the left hand segments into engagement with the contact fingers for hoisting and to bring the right hand segments into engagement with the contact fingers for lowering. The arrangement of the contact segments is such that nine operative positions of the drum are obtained in both hoisting and lowering.

In hoisting the segments 14 and 15" first engage contacts 14 and 15 respectively to close the motor circuit, said segments remaining in engagement with said fingers throughout the hoisting movement of the drum. In the second position the segments 2* and 3* engage fingers 2 and 3 respectively, and thereafter segments 4 to 10 engage their respective fingers successively, to successively short circuit the resistances r to 9", connected in the motor circuit. In the ofi' position segments 11 and 12 engage fingers 11 and 12 respectively for a purpose hereinafter set forth. When the drum is moved to lowering position the segment 11 disengages finger 11, and segments 6 to 10 and 13 and 15 engage their respective fingers, the last two mentioned segments remaining in engagement with their respective fingers throughout the lowering movement of the drum. In succeeding lowering positions the segments 10 to 6 leave their respective contact fingers successively in the order named, and from the fifth to ninth lowering positions the segments 5 to 2 entroller and the results accomplished thereby. Assuming'that the controller is moved to the first hoisting position circuit will be closed from main line L by conductor 20, finger 15, segment 15 to segment 14, finger l4, conductor 21 through the motor armature, series field winding and brake coil by conductor 22 to finger 10, thence through resistances 1" to 1" in series, by conductors 23 and 24 to line L. The brake coil will thus be energized releasing the mechanical break and the motor will start but with all of the resistances 7" to 1" included in circuit therewith. However, as is obvious from the drawing, movement of the controller to the succeeding hoisting positions will short circuit the resistances 1" to r successively thus gradually accelerating the motor. The foregoing connections are illustrated in a simplified form in Fig. 2.

Assuming now that the controller is moved in the opposite direction from full running position, the resistances W to T will be successively reinserted in circuit in the order named, and thereafter the motor circuit will be interrupted by disengagement of the segments 1 1 and 15 from the fingers 14: and 15 respectively. This not only interrupts the motor circuit but also the circuit of the brake coil B, deenergization of which results in the setting of the mechanical brake. The controller will then be. in its off position, in which position as previously stated the segments 11 and 12" engage fin; gers 11 and 12 respectively. 7 This completes a dynamic braking circuit for the motor including the series field as shown in a simplified form in Fig. 3. This braking circuit may be traced from the lower terminal of the motor armature by conductor '21 to contact finger 14, thence through the resistance R to contact finger 12 and segments 12 to segment 11", finger 11, conductor 25 through the field winding F to the opposite terminal of the motor armature.

In practice there are instances where the load will descend of its own weight upon release of the mechanical brake. There are, however, other instances where the load is so light that it will not descend of its own weight and must be continuously driven downwardly or else must be given a kick-off to overcome the inertia of rest.

The controller illustrated provides both for a kick-oil or for continued application of power for lowering. The lowering 0 eration is as followsz-Upon-movement o the controller to the first lowering position a circuit is closed from line L by conductor 20 to finger 15, segment 15 to segment 13*, finger 13, conductor 26 to a point between the armature and series field, at which point the current divides, part passing through the armature by conductor 21 1.4 finger 1 1, thence through the resistance R to finger 12, segment 12 to segment 6 to finger 6. The other branch passes through the field winding F, brake coil B, by conductor 22 to contact finger 10, segment 10 to seg ment 6 and finger 6, where it reunites with the other branch. From this point both branches extend through resistances 1' 1 7" and 1 by conductors 23 and 24 to line L. With these connections which are illustrated in a simplified form in Fig. 4 it will be seen that power is supplied to the motor but that the current flows through the armature in a reverse direction to that previously described, although it flows through the field winding in the same direction as that previously described. Accordingly the motor when starting will operate in a reverse direction to that previously described. Also under these conditions the motor armature and field are connected in parallel circuits with the resistances r r 7 and r in series therewith. The branch including the field winding includes the brake coil, while the branch including the armature includes the resistance R so designed as to cause the desired proportion of current to take the branch including the armature. The brake coil being connected in the field branch will with these connections be energized to release the mechanical brake. The armature and field windings now being connected in parallel the motor will operate as a shunt motor, its speed if it starts under these conditions being regulated by the resistances 7' to r.

If the motor fails to start under these conditions or if higher lowering speeds are desired, the controller is moved to succeeding lowering positions. As the controller is moved to the second, third and fourth lowering positions, the resistances 1", 1'", r and r are successively inserted in the field branch of the motor circuit. This of course gradually decreases the field strength, at the same time increasing the drop in voltage across the armature terminals. This obviously results in increasing the speed of the be obtained by moving the controller to the 5th, 6th, 7th, 8th and 9th positions. This results in successively excluding the resistances 1' 7, 7' and r in the order named. from thearmature circuit, it being remembered that the armature circuit is completed through the'lowering segments. Also during this movement one of the resistance sections mentioned is removed from the field circuit at each step of the controller but reinserted upon the next step. Accordingly during movement of the controller through the 5th, 6th and 7th positions the field strength of the motor will remain practically constant, while the drop in potential acrossthe armature terminals will be gradually increased, thereby gradually increasing the speed of the motor. In the 8th position all of the resistances 7* to W are removed from the armature circuit and section 7" from the field circuit. In the 9th position the resistance section 7" is reinserted in the field circuit.

To briefly review the lowering operation it will be seen that variationin the speed of the motor up to the 4th lowering position is accomplished by insertion of resistancein the field branch of the motor circuit and that from then on to the 8th position the speed variation is obtained by excluding resistance from the armature circuit but including the same in series with the field winding. This gives a wide range of speed variation and also by weakening the-field rior to exclusion of the series resistance rom the armature branch protects the motor against overheating. After the motor has been set in operation its speed may be regulated at will by varying the position of the controller, it being obvious that movement of the controller toward the first loweringposition will gradually decrease the speed of the motor.

In case the load is suiiicient to overhaul and drive the motor after having received a kick-off, the motor will act as a rtor, increasing its generative effect and causing it to act as a dynamic brake to restrict the speed at which the load descends. Va-

riation of this braking efiect may be obtained by movement of the controller to different positions to include or exclude the resistances 7- etc., it being-understood that the greater the amount of resistance included in the local circuit, the less is the dynamic braking effect of the motor. When it is desired to stop the load in its descent, the controller is again thrown to off position disconnecting the motor from the line L and establishing the dynamic brakin circuit aforesaid and deenergizing the bra e coil.

generator vsendlng current from 1ts posltive termlnal I.

What I claim as new and desire to secure by Letters Patent is as follows 1. The method of controlling an electric motor, consisting in connecting the motor armature and series field winding in parallel to supply lines with a common resistance in series with both the armature and field winding and then inserting additional re sistance in the field circuit without variation of resistance between the armature and the supply lines.

2. The method of controlling an electric motor consisting in connecting its armature and series field winding in parallel branches with a common resistance in series with both branches, then insertin field branch of its circult and subsequently varying the armature branch of its circuit to exclude said first mentioned resistance.

3. The method of controlling an electric motor consisting in connecting the motor armature and a fixed resistance to a supply circuit in parallel with the motor field winding and brake coil and then successively re ducing the flow of current through the field winding and brake coil circuit without variation of the resistance between the motor armature and the supply circuit and further varying the electrical conditions in the motor for regulating the speed thereof.

4. The method of reversing and varying the speed of an electric motor having a series field winding consisting. in establishing a closed loop across the terminals of the motor armature including the series field winding, establishing a circuit from points of said loop between the armature and field winding to connect the same in parallel and reverse the flow of current through one of the same and connecting a common resistance in series with both branches, then inserting resistance in the field branch of the circuit, and then enlarging the loop to include said first mentioned resistance, thereby excluding the same from the armature branch.

5. A controller for electric motors comprising resistances, a brake coil and means for connecting the motor armature, series field winding, brake coil and one of said resistances in a closed loop and connecting said loop to supply lines through another of said resistances, the motor armature and said first-mentioned resistance being thereby paralleled with the series field winding and said brake coil, said means being also adapted to thereafter insert more of said resistance in the field branch and insuring the insertion of said resistance prior to variation of resistance between the motor armature and the supply lines.

6. A controller for reversing electric motors, comprising resistances, means for connecting the motor armature and series field winding acrossthe lines in parallel with one of said resistances in the armature branch and another of said resistances in series with both branches, subsequently including another of said resistances in the field branch and thereafter excluding said second mentioned resistance from the armature branch but leaving the same in the field branch.-

7. In a controller for electric motors, in combination, a fixed resistance, a variable resistance, a brake coil and circuit controlling means for connecting the motor armature and said fixed resistance in parallel with the motor field winding and said brake coil. and connecting said parallel circuits to the supply lines through a certain portion of said variable resistance common to both circuits and thereafter inserting the remainder of said variable resistance in the field circuit and varying the armature branch to exclude said first-mentioned portion of said variable resistance but only after insertion of all of said variable resistance in the field circuit.

8. In a controller for electric motors, in combination, a fixed resistance, variable re- .sistance, a brake coil and circuit controlling means for connecting the motor armature, series field winding, said brake coil and said fixed resistance in a closed loop, said means being operable to thereafter connect said loop to the supply lines with the armature and said fixed resistance in parallel with the field winding and said brake coil and thereafter to vary the speed of the motor through the medium of said variable resistance but insuring an increase in the resistance of the field branch of the motor circuit prior to any variation in the resistance between the armature and the supply lines. 7

9. In a motor controller, in combination, a brake coil, a'fixed resistance and means for connecting the motor and brake coil and resistance to a supply circuit with the motor armature and said resistance in parallel with the field winding and said brake coil and thereafter varying the circuit connections to vary the speed of the motor, said means including means insuring a reduction of the current in the field and brake coil circuit upon initial operation of said means and after establishing said first-mentioned connections and without variation of the resistance between the motor armature and the lines.

10. A controller for electric motors comprising means for establishing a dynamic braking circuit to include the motor arma-' ture and series field winding and to establish power connections including said dynamic braking circuit and dividing the same into parallel branches for the motor armature and field winding, a resistance for the dynamic braking circuit, a second resistance included in series with both the branches of said dynamic braking circuit and a third resistance, said means being operable to first insert said third resistance in the field branch of the dynamic braking circuit and afterward remove said second resistance from the armature branch while leaving the same in the field branch.

11. A drum controller for electric motors comprising a series of contact fingers and two sets of contact segments, certain of said fingers and segments controlling the power connection for both forward and reverse operating, other of said fingers and segments establishing a dynamic braking circuit for the motor in off position of the controller and other of said fingers and segments controlling resistances for the motor, said controller when operated to reverse the motor connecting said dynamic braking circuit to the supply circuit through certain of said resistance controlling contacts and segments, certain of said resistance controlling fingers and segments being so arranged as to break contact upon continued reverse movement of the controller to insert resistance in the field branch and other of said resistance controlling fingers and segments being ar ranged to thereafter successively engage to exclude resistance from the armature branch.

In witness whereof, I have hereunto subscribed my name in the presence of two witnesses.

NIELS Ll MORTENSEN.

Witnesses:

FRANK H. HUBBARD, WALTER E. SARGENT. 

